ROLE OF THE PROSENCEPHALON IN SHIVERING 
Respiration was recorded by a strain gauge (Statham Laboratory, 
Model P23B) transducer from a rubber chest tambour. Fronto- 
occipital EEG waves were recorded from stainless steel electrodes 
that pierced the calvarium to lie on the dura above the medial edge 
of the sigmoid gyrus and the posterior margin of the suprasylvian 
gyrus. 
The head of each preparation was mounted in the stereotaxic 
frame (Labtronics, Inc., stereotaxic instrument Model No. 4), the 
scalp skin reflected after midline skin incision, and the temporal 
muscles retracted from these origins and sufficient calvarium re- 
moved to expose the dorsal aspect of the marginal gyrus. The stim- 
ulating electrode was stereotax ically inserted into the hypothalamus, 
and at each point of insertion, the dura was minutely cut to permit 
passage of the electrode into neural tissue. The hypothalamus was 
unilaterally stimulated in planes 0.5, 1.5, 2.5, and3.5 mm from the 
midline and EEG, respiration, somatic, and visceral changes re- 
corded and/or noted by independent observation. In each given 
experiment the locus of any stimulated site was 1 mm dorsal or 
ventral and/or 1 mm medial or lateral to any other stimulated site. 
Throu^out these experiments an attempt was made to maintain the 
animal's rectal temperature at 38.5 C to 37.5 C by appropriate 
adjustments of environmental temperature. At the conclusion of each 
experiment the brain was fixed in formalin, sectioned every 80^ in 
the plane of the electrode tracts and each alternate section stained 
with buffered thionine. In this way all stimulated sites could be 
confirmed histologically. The schemata of brain electrode tracts 
in subsequent figures are based on such histology. Table V is a 
key to the abbreviations of nomenclature used in these schematics. 
Results. In detailed mapping of the hypothalamus for a shivering 
response to electrical stimulation, the animals were stimulated 9 
to 24 hours after injection of 40 to 60 mg/kg alpha chloralose. 
Figure 3 illustrates the necessity for the long delay between induc- 
tion of anesthesia and initial stimulation. In this particular experi- 
ment, the effects of septal and posterior hypothalamic stimulation 
responses were compared on the ipsilateral side of the brain in 
which stimuli were applied 10, 23 to 24, and 32 to 33 hours after 
beginning anesthesia. As shown in Figure 3 neither posterior hypo- 
thalamic stimulation nor septal stimulation produced a somatic 
response nor a change in respiration rate 10 hours after alpha 
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